This invention relates to roof-mounted support apparatus suitable for supporting such things as ducts, pipes, cables, air conditioning units, and roof access ladders.
In modern commercial and industrial buildings particularly those having flat roofs, it is often desirable to locate or mount a variety of structures on the roof of the building. For example often air conditioners are mounted on the roof and there may also be pipes or duct work. It may also be necessary to provide a means for attaching guy wires required to support chimneys, T.V. towers or the like. Further devices that may require support on a roof include roof access ladders and window cleaning safety lines. In constructing support apparatus for roofs, it is necessary that the apparatus not create any water leaks in the roof and that it have a long maintenance-free life. Another desirable characteristic for such supports, particularly with the present day high cost of energy, is that they not result in high heat losses due to a lack of insulation in the region of the support apparatus.
One known method for anchoring or supporting and flashing roof items is called the pitch pan method. A "pitch pan" anchor is provided by means of a centre support post mounted on a flat base plate and a separate circular or square sleeve member having a flange projecting from its bottom end. The sleeve member extends around the centre post and leaves a gap between itself and the post which is filled with mastic cement intended to provide a waterproof seal. There are severe maintenance problems with the use of this method because the mastic cement will soon dry and shrink and the shrinking can leave a gap between the cement and either the post or the sleeve member. Also if the post moves slightly for any reason, a gap through which water can leak will be created. It is not uncommon for a roof support constructed in accordance with the pitch pan method to require maintenance or repair after as little as nine months from the initial installation or the last repair thereto.
Early U.S. Pat. No. 880,560 issued Mar. 3, 1908 to Sidney Milroy teaches a support for mounting a hand pump on a concrete base. The support includes a hollow cylinder having angle strips extending outwardly therefrom, which strips are embedded in the concrete. The upper end of the cylinder is threaded and is connected by the threads to a flange member. By means of holes in the flange and bolts, the base of the pump can be connected to the flange.
A much more recent U.S. Pat. No. 4,120,129 issued Oct. 17, 1978 to W. M. Nagler describes a special flashing unit designed for use on a roof and arranged about a vertical pipe extending through the roof. The unit is not intended for anything other than the provision of weather-proof egress for a single pipe. The unit has a hollow housing and an integral circular base flange. The housing tapers outwardly from the upper end to the flange. There is also a hollow sealing element having a number of concentric upstanding stepped sections. The bottom of the sealing element is sized to closely fit the upper end of the housing to which it can be clamped by means of a standard pipe clamp.
It is an object of the present invention to provide a reliable roof-mounted support apparatus having a long, useful life and adaptable by means of various embodiments for the support of a number of common roof items.
It is a further object of the invention to provide a novel roof-mounted support apparatus wherein the likelihood of a water leak developing around or through the support apparatus is substantially reduced, if not eliminated.